This invention belongs to the field of poultry husbandry and provides new methods and compositions for the control of coccidiosis of poultry. The damage done by coccidiosis is well known. All of the economically reared poultry species are subject to infections of coccidia, which cause severe losses unless controlled. Coccidial infections not only cause the infected birds to gain weight more slowly than normal, and to convert their feed inefficiently, but often result in the deaths of large numbers of birds.
Like most parasitic infections, coccidiosis is most frequent and most damaging in flocks of birds reared in conditions of high population density. Since these conditions are also the most economical, modern efficient poultry operations are very likely to suffer severely from coccidiosis.
All of the coccidiocides used in this invention are known in the animal health art. References describing the compounds and their preparation will be cited below. The novelty of the present invention resides in the discovery that the compounds, when combined in proper amounts or concentrations, are synergistic. The coccidiocidal effect of the combinations is greater than the effect which could be expected from the known effects of the components of the combination, when used alone. Thus, use of the combinations allows the poultry grower to obtain economically satisfactory coccidiocidal effect with the administration of unusually small amounts of the coccidiocides. Small dosages not only have the obvious economic benefit, but also are likely to result in reduced residues of coccidiocide in the edible tissues of the poultry.